code: def _masked_crc(data: bytes) -> bytes:
      """CRC checksum."""
      import crc32c
  
      mask = 0xA282EAD8
      crc = crc32c.crc32(data)
      masked = ((crc >> 15) | (crc << 17)) + mask
      masked = np.uint32(masked & np.iinfo(np.uint32).max)
      masked_bytes = struct.pack("<I", masked)
      return masked_bytes
  
file_path: ray/python/ray/data/datasource/tfrecords_datasource.py
imports: import struct
  from typing import TYPE_CHECKING, Dict, Iterable, Iterator, List, Optional, Union
  import numpy
  from ray.data.block import Block
  from ray.data.datasource.file_based_datasource import FileBasedDatasource
  from ray.util.annotations import PublicAPI
label_desc: Use image node_id 8 for calling a global function with example usage: _masked_crc(data) and returns: masked_bytes